autobooting FreeBSD on Black Bird

[Mark Linimon]

Now that I look at it, I see the following in the log (when
I interrupt the boot):

 [enP4p1s0f0] Processing DHCP lease response (ip: 192.160.235.178)
 [enP4p1s0f0] Probing from base tftp://192.160.235.99/pxelinux.cfg/
 [enP4p1s0f0] PXE autoconfiguration failed

So somehow I haven't set something to tell it "you aren't going to
find pxelinux.cfg there so don't bother".

mcl